Electrical power systems rely on three-phase transmission lines to deliver electricity efficiently over long distances. However, faults such as line-to-ground (LG) faults are among the most common disturbances in transmission systems. These faults occur when one phase conductor accidentally encounters the ground due to insulation failure, lightning, equipment malfunction, or environmental conditions. Such faults can lead to power outages, equipment damage, and system instability, making rapid detection and accurate fault location essential for maintaining reliable power supply. This project focuses on the detection and monitoring of line-to-ground faults in a three-phase transmission line and determining the exact location of the fault. The proposed system uses sensors and monitoring circuits to continuously measure electrical parameters such as voltage and current in each phase. When a fault occurs, the abnormal variations in these parameters are detected by the control unit, which identifies the faulty phase and triggers protective actions. The system also incorporates a fault location technique that estimates the distance of the fault from the monitoring station based on changes in line impedance or voltage levels. The detected fault information is then displayed through a monitoring interface or transmitted to a control center, enabling quick maintenance response and faster restoration of power. By implementing this system, the reliability and safety of transmission networks can be improved. The proposed method helps reduce fault detection time, maintenance costs, and power interruption duration, thereby enhancing the overall performance of the electrical power distribution infrastructure.

Keywords: Three-phase transmission lines; Line-to-ground fault; Fault detection; Fault location; Arduino UNO; ACS712 sensor; Smart monitoring.